I recently built up a set for myself - 20/24 spokes using Kinlin XR-300 rims. I did the rear 2x + half radial. I'm really happy with the set so far, I've beat up on them already and they seem completely solid. The XR-300 is a heavier rim at 495g on my scale, but even using a heavy (370g) Shimano rear hub the set still comes in at 1696g.
If you did that same build with XR-200s and a ~250g rear hub you'd be looking at a sub-1400g set that should still be strong enough. Or go with an XR-270 in the rear for a little insurance. (BTW I weigh 135lb.)